Cover operating mechanism for soaking pit furnaces



n 1942. H. F. SPENCER 2528?,645"

COVER OPERATING MECHANISM FOR SOAKING 'rn FURNACES original FiIedDec.17, 1937 s 1 ATTORNEY.

June 23, 1942. S N

COVER OPERATING MECHANISM FOR SOAKING PI-T FURNACES Original-F1196; Dec.17, 1937 3 sheets sheet 2 INVENTOR.

ATTORNEY.

June 23,1942. F. js'l sNa COVER OPERATING MECHANISM FOR SOAKINGPIT"FURNACES Original Filed 1590.17, 1937 3 shets sheet 5 IN VENTQR. W4 75%7 Wa 4 ATTORNEY.

Patented June 23, 1942 COVER OPERATING MECHANISM FOR SOAKING PITFURNACES Howard F. Spencer, Pittsburgh, Pa., assignor to Amco,Incorporated, Pittsburgh, Pa., a corporation of Pennsylvanla w Originalapplication December 17, 1937, Serial No. 180,337. Divided and thisapplication April 21, 1938, Serial No. 203,337

3 Claims. (01.288-10) This invention relates to new and usefulimprovements in cover cranes for soaking pit furnaces or the like, andthe present application is a division" of my application seriallynumbered 180,337 filed December 17, 1937. It is among the objects of theinvention to provide a crane or cover operating mechanism for raising,traversing and lowering the cover of pit type furnaces. which shall beoperated by remote control.

Another object of the invention is the provision of a control circuitfor automatically energizing and deenergizing the cover operating andtraversing motorslin coordinate relation as will be hereinafter stated.I

Still another object of the invention is the provision of a coveroperating mechanism-which shall employ a lever arm suspension forsupporting and for raising and lowering the cover mechanism relative tothe carriage by an eccentric drive in which the cranks are ondead-centers in both the lowered or retracted positions of the furnacecover, thereby avoiding the necessity of more positive lift positioningmechanism and providing against the imposition of unnecessary strain onthe operating parts by balancing the weight of the cover on theeccentric shaft.

These and other objects of the invention will become more apparent froma consideration of the accompanying drawings constituting a part hereofinwhich like reference characters designate like parts and in which:

'Fig. 1 is a plan view of a cover operating mech anism embodying theprinciples of this invention;

Fig. 2 a side elevational view thereof;

Fig. 3 a front elevational view of the cover and cover operatingmechanism;

Fig. 4 a cross-section taken through the end frame of the cover carriageshowing the drive mechanism for hoisting the carriage;

Fig. 5 a front elevational view partially in section of the cover andcarriage; and

Fig. 6 a wiring diagram of the cover lift and traversing motors withcontrol panels and limit switches, and also showing the control systemcoupled to the blower control.

Cover structure With reference to Figs. 1 m5 inclusive of the drawings,the numeral I designates a cover member constructed of channel bars 2and 3, on which are supported refractory brick l, the bottom peripheryof the cover being provided with a depending flange 5 of a plurality ofalloy members entire top of the furnace opening, the inner furnace wallbeing designated by the reference character 6. The cover I is adapted tobe raised and lowered by a carriage generally designated by the numeral8, the cross-beams of which are supported on I-beams 9, resting oncastings Ill, which are provided with wheels II that engage a pair ofrails l2 mounted adjacent and parallel to the furnace walls, as isclearly shown in Fig. 5 of the drawings. The carriage 8 is adapted totraverse the rails by operation of a drive mechanism comprising.gearwheels l3 and I4, Fig. 4, and pinions l5, the latter being actuatedby a shaft is that is driven by a reversing motor ll, Fig. 1, through agear transmission la. The coveri is suspended from the carriage 8 bymeans of links l9 and 20 joined by a threaded nut or turn-buckle H foradjusting the length of the links. the links l9 being pivoted at 22 to abracket 23 attached to the cover member and links 20 being pivotallyconnected to. a bell-crank lever N mounted on a. shaft 25. Thebell-cranks are subjected to oscillatory movement by the connecting rods26 and 21, the lever 24 being in the normally lowered position, as shownin Fig. 2 of the drawings. Rods 26 and 21 are provided with ec centricconnections 28 and 19 to shafts 30 and 33 that are actuated through atransmission 3| by hoisting motor 32. The operating shaft 33 extendsacross a cover to operate a second set of actuating rods 26 and 21 andtheir connected linkage to lift the cover at four points.

As shown in Fig. 2, a guide link 35 is provided to stabilize the coverin its raising and lowering movements, this link being pivotallyconnected to a bracket 35 on the cover, as shown in Fig. 5. A grill-work36 and 31 is provided for safe access to the operating parts.

Cover operating control mechanism A limit switch 38, Figs. 1 and 3, isconnected to the operating shaft 30 of the cover lifting mechanism andthis switch remains open from zero -to 180 rotation of theshaft 30, andis closed from 180 to 360 rotation of the shaft 30.

Other controls of the cover lift and carriage are shown in Fig. 6 of thedrawings, wherein all of the-controls to the left of the vertical centeri line are on the carriage and all of the controls to t t engage a dseal 5 extending u d th these switches being operated by the position ofthe carriage on its track. Limit switch 40 controls the position of thecrane motion while travelling in reverse direction. Limit switch 4icontrols the crane motion while travelling in forward direction. Thelimit switches 40 and 4| stop the carriage when it is in its correctposition over the pit, ready for lowering the cover I.

A cover control panel 42 is connected across the line of the cover liftmotor and is a'standard magnetic control. The cover lift motor 32 is ofthe standard squirrel-cage type and rotates in one direction only. Themotor is provided with a springloaded magnetic brake, designated by thenumeral 43, which acts immediately upon the stopping of the motor 32.The numeral 44 designates a traversing control panel which is a standardmagnetic control across the line of the traversing motor II, which isalso a squirrel-cage type connected with the traversing control, to bereversed at will. It is also provided with a springloaded magnetic brakedesignated by the numeral 45, which is applied upon stopping of themotor II.

All of the above-mentioned control equipment is mounted on the covercarriage and connected to the controls that are manipulated b theoperator through a fiexiblewire cable 46 and cablewinding reel 39. Thefollowing equipment shown on the right hand side of the cable-windingreel 39 is stationary and controlled by the operator or by limitswitches. Limit switch 41 stops the carriage at 50% of its reversetravel, namely, when the pit cover is half open. Limit switch 48 stopsthe carriage at 100% of its reverse travel when the pit is completelyuncovered. Limit switch 49 stops the carriage when it has travelled 50%in the forward direction with the cover half open and limit switch 50stops the crane when it has reached its full forward position, in whichthe pit is completely uncovered.

The numeral designates a master control switch, which determines thedirection of movement of the cover carriage and also the extent of itstravel in either direction, this switch having control of the covertraversing at all times and can stop the cover traversing at any timewhen moved to the neutral position.

The numeral 52 designates a cover control switch which determines theposition of the cover lift mechanism, that is either up or down to openand close, the pit switch 53 controlling the cover raising movement, andswitch 54 the cover lowering movement. Push button switch 55 controlsthe blower motor 55 for supplying air to the gaseous fuel in the pit.The switch 55 will not start the blower motor 56 unless limit switch 51is closed, this switch being opened when the cover is raised. Thenumeral 58 designates the control panel for the blower motor 55.

The operation of the carriage and the above described control mechanismis briefly as follows: The carriage 8 is normally positioned centrallyof the pit furnace with the cover I grounded in the seal 6, as shown inFig. 5. When the ingots in the furnace have attained the rollingtemperature, the operator, by means of the controls shown in Fig. 6,energizes the hoisting motor 32 to actuate operating shafts 30 and 33,causing rods 25 and 21 to move the bell cranks 24 to raise the cover Iout of the seal 6. The operator then energizes the motor I'I to traversethe carriage 8 in either direction, forward or reverse, depending uponthe side of the pit which it is desired to expose for the removal ofingots. After the ingot is removed or an ingot is charged, as the casemay be, he reverses the carriage and then energizes the hoisting motorto lower the cover, the cover and carriage motors, as well as the blowermotor, being interlocked by the electrical controls to coordinate theirfunctions, as will be apparent from a description of the operation ofthe control mechanism as follows:

With the cover seated on the pit in the seal 6, if the operator desiresto move the cover I forward 50% to half open the pit closure, pushbutton switch 53 is depressed and the master control switch 5| is movedto the forward position. The closing of these switches completes thecircuit from the power line through the cover control master switch 42,limit switches 41 and 48, limit switches 40 and 4|, to energize coverlift motor 32, which at the same time releases magnetic brake 43 onmotor 32. As the cover I is raised, limit switch 51 opens, thusdeenergizing the blower motor 56 through the control panel 58. When thecover I has reached the top of its travel, limit switch 38 closes, whichcompletes the circuit that stops the lifting motor 32 and appliesmagnetic brake 43 at the same time magnetic brake 45 of the traversingmotbr I1 is released, motor I I is energized, and the carriage traversesforward 50% of its total travel, until it comes in contact with limitswitch 41, which opens the traversing motor control circuit and stopsthe carriage.

If it is desired to move the carriage the additional 50% of possibletravel, the master control lever of switch 5| is pushed farther in theforward position, which closes an additional contact that shorts-outlimit switch 41 and the crane travels forward until it strikes limitswitch 48,

which again stops the carriage when it reaches of its possible travel ina forward direction. While the traversing motor I! is operating, thecontrol circuit of the cover lowering mechanism is deenergized,rendering it inoperative. Unless limit switches 40 and M are closed, itis impossible to raise or' lower the cover I. These limit switches areclosed only when the carriage 8 is in position directly over the pit.

To move the cover I back to position over the pit, it is merelynecessary to depress push button switch 54 to lower the cover. The cranethen traverses to the position over the pit and allows limit switch 40to open, thus stopping motion of the carriage and starting coveroperating motor 32. The cover I is lowered until limit switch 38 opensand stops motor 32. As the cover lowers limit switch 51 closes andstarts blower motor 56, and all parts of the control circuit are thusreturned to their original position.

To move the cover I in the reverse direction, the control goes throughthe reverse contacts of the master controller 5|, and the other controlsfunction in the same manner as described above.

Although one embodiment of the invention has been herein illustrated anddescribed, it will be obvious to those skilled in the art that variousmodifications may be made in the details of construction withoutdeparting from the principles herein set forth.

I claim:

1. A cover operating mechanism comprising a carriage, a cover suspendedfrom said carriage, means for actuating the cover suspension to raiseand lower the cover, said means comprising a plurality of hell cranklevers having one arm linked to the cover, a drive shaft havingoppositely disposed cranks connected by rods to the other arm of saidlevers, the angular disposition a en s .7 of the cranks and levers beingsuch as to lock the cover actuating levers in both the lowered andretracted positions of the cover.

2. A cover operating mechanism comprising a carriage, oppositelydisposed bell crank levers 1 pivotally supported on the carriage, linksdeposition of the cranks and levers being such as to lock the coveractuating mechanism in its raised and lowered position.

3. A cover operating mechanism comprising a carriage; oppositely bellcrank levers pivotally supported onv the carriage, said bell cranklevers having one arm extending upwardly and the other arm extendingoutwardly in opposite directions, links depending from the outwardlyextending arms, a cover suspended by said links, a drive shaft'supportedintermediate of and parallel to the pivotal axes of said oppositelydisposed bell crank levers, a crank means on said shaft connected by arod to the upwardly extending arm of each bell crank, the crank means ofoppositely disposed bell cranks being displaced at 180 degrees, therebybalancing the torque load on the drive shaft, and means-Q for actuatingthe drive shaft to raise and lower the cover. I

HOWARD F. SPENCER.

